Behavior change management¶

Overview¶

Snowflake implements behavior changes monthly in bundles included in regularly-scheduled releases. During the testing period and opt-out period for each behavior change bundle, you can enable or disable the bundle in your account. This document explains how to check whether a particular bundle is enabled in your account and how to enable or disable it.

In this document, the name of the behavior change bundle is in the form YYYY_NN. For the names of the currently available behavior change bundles, see Behavior change log.

Checking the status of a behavior change bundle in your account¶

To check whether a specific behavior change bundle is enabled in your account, call the SYSTEM$BEHAVIOR_CHANGE_BUNDLE_STATUS function. For example, to check the status of the bundle named 2024_02:

SELECT SYSTEM$BEHAVIOR_CHANGE_BUNDLE_STATUS('2024_02');

+-------------------------------------------------+
| SYSTEM$BEHAVIOR_CHANGE_BUNDLE_STATUS('2024_02') |
|-------------------------------------------------|
| DISABLED                                        |
+-------------------------------------------------+

To check the status of all currently available behavior change bundles, call the SYSTEM$SHOW_ACTIVE_BEHAVIOR_CHANGE_BUNDLES function:

SELECT SYSTEM$SHOW_ACTIVE_BEHAVIOR_CHANGE_BUNDLES();

+--------------------------------------------------------------------------------------------------------------+
| SYSTEM$SHOW_ACTIVE_BEHAVIOR_CHANGE_BUNDLES()                                                                 |
|--------------------------------------------------------------------------------------------------------------|
| [{"name":"2023_08","isDefault":true,"isEnabled":true},{"name":"2024_01","isDefault":false,"isEnabled":true}] |
+--------------------------------------------------------------------------------------------------------------+

Enabling a behavior change bundle in your account¶

To enable a particular behavior change in your account, call the SYSTEM$ENABLE_BEHAVIOR_CHANGE_BUNDLE function. For example, to enable the bundle named 2024_02:

SELECT SYSTEM$ENABLE_BEHAVIOR_CHANGE_BUNDLE('2024_02');

+-------------------------------------------------+
| SYSTEM$ENABLE_BEHAVIOR_CHANGE_BUNDLE('2024_02') |
|-------------------------------------------------|
| ENABLED                                         |
+-------------------------------------------------+

Disabling a behavior change bundle in your account¶

To disable a particular behavior change in your account, call the SYSTEM$DISABLE_BEHAVIOR_CHANGE_BUNDLE. For example, to disable the bundle named 2024_02:

SELECT SYSTEM$DISABLE_BEHAVIOR_CHANGE_BUNDLE('2024_02');

+-------------------------------------------------+
| SYSTEM$DISABLE_BEHAVIOR_CHANGE_BUNDLE('2024_02')|
|-------------------------------------------------|
| DISABLED                                        |
+-------------------------------------------------+

Determining the current version of your account¶

To check the current version of Snowflake that is in your account, call the CURRENT_VERSION function. For example:

SELECT CURRENT_VERSION();

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+-------------------+
| CURRENT_VERSION() |
|-------------------|
| 8.5.1             |
+-------------------+

Mitigating masking policy return value updates¶

In the 2024_04 bundle, there are changes to the values for precision and scale in masking policy conditions (collectively: “return value updates”). A query on a column protected by a masking policy fails when the following are true:

• The bundle is enabled.

• The masking policy conditions return a value whose precision is greater than the precision of the column to which the masking policy is assigned.

If the scale of the return value is larger than the scale of the column, the value is truncated to match the scale of the column.

If you want to apply the new behavior to a pre-existing policy, create a new masking policy and replace the pre-existing policy using the FORCE keyword.

When the bundle is enabled, you can test the behavior as follows:

1. Create a policy:

   CREATE MASKING POLICY MP AS (s string)
   RETURNS STRING -> 'abcdef';
   

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2. Assign the policy:

   CREATE TABLE t(col1 string(2));
   
   ALTER TABLE t MODIFY COLUMN col1 SET MASKING POLICY mp;
   

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3. Query the column (fails):

   SELECT * FROM t;
   

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To determine the impact of this change and provide enough time to update the masking policy conditions to protect data, query the SNOWFLAKE.BCR_ROLLOUT.BCR_2024_03_DDM_ROLLOUT view to understand how the future return value updates affect your account.

The BCR_2024_03_DDM_ROLLOUT view is temporary. Snowflake will remove the view when the return value updates are generally enabled in a future behavior change bundle. At this point, you will not be able to query the view to determine affected columns and policies or prevent column query or masking policy assignment operation failures due to return value updates.

The view records data starting from March 2024. If a query on the view takes a long time to complete, you can specify the start date and end date session variables using a SET command. These variables help to reduce the number of rows to evaluate when you query the view. For example:

SET DDM_CASTING_BCR_START_DATE = '2024-03-01';
SET DDM_CASTING_BCR_END_DATE = '2024-04-03';

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